In recent years, with the rapid development of the world economy and the Chinese economy, vehicles have become a highly popular means of transportation in many countries in the world, including China. Moreover, the penetration rate of vehicles will continue to increase. While vehicles bring convenience to people's lives, they also inevitably have some negative impacts on humans, such as traffic accidents, urban congestion, and environmental impacts. From the perspective of traffic accidents, taking China as an example, there were 204,196 traffic accidents in 2012, with 59,997 deaths, 224,327 injuries and direct property losses of 1.175 billion yuan.
With the rise of the Internet of Vehicles technology, the above problems can be solved to some extent. The Internet of Vehicles refers to a large system network for wireless communication and information exchange between the vehicle-X (X: car, road, pedestrian and Internet) in accordance with the agreed communication protocol and data interaction standards. There are three different types of the Internet of Vehicles communication: Vehicle to Vehicle (V2V), Vehicle to Infrastructure (V2I), and Vehicle to Pedestrian (V2P), which are collectively referred to as V2X communication. In V2I communication, Infrastructure can also be called a Road Side Unit (RSU).
In solving the problem of traffic accidents, the V2V and V2I systems can avoid 83% of light vehicle accidents and 79% of heavy truck accidents respectively. After being deployed in the United States, V2V technology can help avoid 25-592 thousand traffic accidents per year, save 49-1083 lives, avoid 1.1-27 million injuries, and reduce 31-728 thousand property-only accidents. In addition, V2X technology can also solve problems such as urban congestion and environmental pollution. For example, vehicle fuel consumption and carbon dioxide emissions are reduced by 2.3% through only an application of V2X in-vehicle speed limit alert.
Currently, the 3rd Generation Partnership Project (3GPP) is has begun research on V2X communication based on Long Term Evolution (LTE). In Device to Device (D2D) communication mode of the LTE system, when a service needs to be transmitted between user equipments (UEs), data of the service between the UEs is not forwarded by the base station, but is directly transmitted by the source UE to the target UE through the air interface. FIG. 1 is a schematic diagram of a D2D communication structure in the related art. As shown in FIG. 1, this communication mode has characteristics that are distinct from the communication mode of the traditional cellular system. For V2V communication of the Internet of Vehicles, the D2D communication mode is used, thereby achieving the effects of saving wireless spectrum resources, reducing the data transmission pressure of the core network, reducing system resource occupation, increasing the spectrum efficiency of a cellular communication system, reducing the transmit power consumption of a terminal and saving network operation costs to a large extent.
In V2X communication, some features and requirements of V2X communication include that V2X communication requires high communication reliability, the number of devices participating in communication is huge, and resource congestion is prone to occur. In addition, in V2P communication, the battery capacity of the handheld terminal held by pedestrians is limited, and it is necessary to additionally consider the energy saving problem of the handheld terminal of the pedestrian in V2P communication.
No efficient solution has been provided to meet requirements and solve problems of V2X communication in the related art.